1. iC3: Centre for ice , Cryosphere, Carbon and Climate, Department of Geosciences, , Dramsvegen 201, 9014 Tromsø , Norway
2. UiT—The Arctic University of Norway , Cryosphere, Carbon and Climate, Department of Geosciences, , Dramsvegen 201, 9014 Tromsø , Norway
3. MARUM—Center for Marine Environmental Sciences , University of Bremen, Leoberner Str. 8, Bremen 28359 , Germany
4. Aix Marseille Université, CNRS, IRD, INRAE, CERGE , Technopole Environnement Arbois-Méditerranée BP 80 13545 Aix-en-Provence, Cedex 04 , France
5. Institute of Marine Research, Oceanography and climate research group, Fram Centre , Hjalmar Johansens gate 14, 9007 Tromsø , Norway
6. School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton , European Way, Southampton SO14 3ZH , UK